FULL PRODUCT VERSION :
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b18)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b18, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Win 7 64bit

A DESCRIPTION OF THE PROBLEM :
This seems to be a simple copy paste error in de BidirectionalBinding method
It seems property2 shoud not be cast to ObservableValue but Observable or the other way round (instanceof should be ObservableValue)

 public static void unbind(Object property1, Object property2) {
        checkParameters(property1, property2);
        final BidirectionalBinding binding = new UntypedGenericBidirectionalBinding(property1, property2);
        if (property1 instanceof ObservableValue) {
            ((ObservableValue) property1).removeListener(binding);
        }
        if (property2 instanceof Observable) {
            ((ObservableValue) property2).removeListener(binding);
        }
    }

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Execute the attached test case

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
unbindBidirectional(a,b) should unbind the content of both lists
ACTUAL -
Classcast Exception is thrown

java.lang.ClassCastException: com.sun.javafx.collections.ObservableListWrapper cannot be cast to javafx.beans.value.ObservableValue
at com.sun.javafx.binding.BidirectionalBinding.unbind(BidirectionalBinding.java:108)
at javafx.beans.binding.Bindings.unbindBidirectional(Bindings.java:795)
at ch.schiller.semaft.UnbindTest.testOnCreate(UnbindTest.java:22)

REPRODUCIBILITY :
This bug can be reproduced always.

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import javafx.beans.binding.Bindings;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import org.junit.Test;

/**
 *
 * @author Patrick.Schmid
 */
public class UnbindTest
{

  @Test
  public void testOnCreate()
  {
    ObservableList a = FXCollections.observableArrayList();
    ObservableList b = FXCollections.observableArrayList();

    Bindings.bindContentBidirectional(a, b);
    Bindings.unbindBidirectional(a, b);
  }
}

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